Spark Double + River Kelpie + Ashnod's Altar

Spark Double
River Kelpie
Ashnod's Altar

Requires
All permanents on the battlefield. Spark Double on the battlefield as a copy of River Kelpie.
Steps
  1. Activate Ashnod's Altar by sacrificing Spark Double, adding cc
  2. When Spark Double dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
  3. As Spark Double enters the battlefield, choose to have it enter the battlefield as a copy of River Kelpie with a +1/+1 counter on it
  4. When Spark Double enters the battlefield, it and River Kelpie's first abilities trigger
  5. Resolve both triggers, causing you to draw two cards
  6. Repeat
Results
Infinite card draw. Infinite draw triggers. Near-infinite colorless mana. Near-infinite ETB. Near-infinite LTB. Near-infinite death triggers. Near-infinite sacrifice triggers.